P0420 on JEEP PATRIOT — Catalyst System Efficiency Below Threshold Bank 1

Q: "What does P0420 mean on a JEEP PATRIOT?"

"P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 2 JEEP PATRIOT owners have reported this to NHTSA."

Q: "What are the most common causes of P0420 on JEEP PATRIOT?"

"Based on 2 NHTSA reports, the most commonly cited components are: Unknown Or Other,Fuel/Propulsion System, Engine And Engine Cooling. These percentages are based on the component field in owner complaints."

Q: "Is P0420 serious on my JEEP PATRIOT?"

"Of 2 NHTSA reports for this code on JEEP PATRIOT, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my JEEP PATRIOT shows P0420?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What P0420 Means on Your JEEP PATRIOT

P0420 is a diagnostic trouble code indicating: Catalyst System Efficiency Below Threshold Bank 1. This code relates to the emission controls system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

2 JEEP PATRIOT owners have reported this issue to NHTSA across model years 2011-2016. Most reports come from the 2011, 2016 model years. The most commonly reported component is Unknown Or Other,Fuel/Propulsion System (50.0% of reports).

Real JEEP PATRIOT Owner Reports

Source: NHTSA Complaints Database

"My jeep started throwing codes p0420, which is saying the catalyst efficiency is below threshold, aka catalytic converter. there have been recalls for this make, model, and year already. i find it hard to believe my car just so happens to not be one of the vehicles to be recalled."

— 2011 JEEP PATRIOT owner · UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM · Filed 01/22/2020

"Tl* the contact owns a 2016 jeep patriot. the contact stated that the check engine warning light illuminated and remained illuminated. the contact performed a diagnostic test on the vehicle himself and retrieved failure code: p0420 catalytic system efficiency below threshold."

— 2016 JEEP PATRIOT owner · ENGINE AND ENGINE COOLING · Filed 09/09/2020

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

1

'11

1

'16

Common Causes on JEEP PATRIOT

Based on NHTSA complaint component analysis for this vehicle.

UNKNOWN or OTHER,FUEL/PROPULSION SYSTEM 50%

ENGINE and ENGINE COOLING 50%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P0420 mean on a JEEP PATRIOT? ▾

P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 2 JEEP PATRIOT owners have reported this to NHTSA.

What are the most common causes of P0420 on JEEP PATRIOT? ▾

Based on 2 NHTSA reports, the most commonly cited components are: Unknown Or Other,Fuel/Propulsion System, Engine And Engine Cooling. These percentages are based on the component field in owner complaints.

Is P0420 serious on my JEEP PATRIOT? ▾

Of 2 NHTSA reports for this code on JEEP PATRIOT, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my JEEP PATRIOT shows P0420? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.